With the availability of high-powered graphics workstations, a number of tools have been developed for the capture of engineering designs, such as electronic designs, mechanical designs, and software designs. Once captured, analysis, synthesis and evaluation may be performed on the design, for example logic simulation or printed circuit layout. Many tools exist for performing the analysis, synthesis or evaluation and many more are certain to be developed in the future.
Historically, schematic capture systems--used to document a design, and analysis tools--such as circuit simulation, were developed separately. More recently, these have been combined into a single design capture system to facilitate their use with a design. In such a system, the capture of the design is separate from the analytical tools. First the designer inputs the design into a graphics system, which displays the design for visual checking. After the design is input, it may be sent to the analytical tools for evaluation, or it may be sent to synthesis tools such as printed circuit layout. Because of the nature and size of these tools, they have been developed independently, often by different companies.
Typically a system from a single company will support documentation, simulation and printed circuit layout. Since all these tools are supplied by a single source, the graphics symbol used for documentation, and the circuit model used in simulation are linked together. A problem arises however, when a model for a particular circuit component is not available on a design capture system, or when simulation at different levels of accuracy is desired. Because of the high growth rate and availability of semiconductor components, it has been difficult for modelers to keep pace. As a result several different modeling companies and modeling technologies have emerged, and several different models often exist for a given component. Different models often are desired to simulate a circuit at different levels of accuracy, for example behavioral simulation or gate level simulation, or to perform different simulation analyses, for example logic, timing, or fault analysis.
Because the graphics symbol and model for a component are linked, each different model has a unique symbol. If a user desires to simulate a captured schematic with a different model, the user must translate the existing symbols into the new symbols, and redraw the schematic using the new symbols. Problems arise when the symbols do not readily translate. This translation takes time, because the user must delete the old symbol and insert the new symbol into the schematic.
In addition, since graphic symbols require considerable storage space, the storage of separate symbols occupies valuable disk storage space on the design capture system. Extra symbol development time is needed to develop the different symbols for different models. Often the different models will have considerable common information, however, since these models are completely separate, this information must be converted or recreated along with the symbol, with possible effects on data integrity when converting from one model to another. Integration of the models from a new vendor requires that a new graphics library be integrated, which delays and complicates the integration. Also, with the symbols and models combined, each model developer is free to create a different user interface between the symbols and the models, and often this user interface is inconsistent between different models.
There is a need in the art then for a design capture system that uses a single graphics symbol for a plurality of circuit models contained in the system. There is a further need for such a system that does not require redrawing the schematic graphics when a different model is chosen. Another need is for such a system that reduces storage space for the symbol library, and reduces symbol development time. Yet another need exists for such a system that maintains data common to a component in a common location to increase data integrity and reduce storage space. Still another need is to provide a system having a consistent user interface. A still further need is for such a system that facilitates new model integration by eliminating the requirement to integrate a new symbol.